This is an undated handout photo of a polar bear taken in the Arctic National Wildlife Refuge. More than two-thirds of the world's polar bears will be killed off by 2050 - the species completely gone... (Associated Press)

(Newser)
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Arctic ice has shrunk so significantly this past summer that scientists fear the region is at a dangerous "tipping point" that could trigger accelerated melting and dangerous consequences for weather patterns and environments. Ice shrank 20% below 2005’s record low. Scientists theorize that the darker sea holds more heat than the reflective ice and will cause even more melting more quickly.

Some experts believe that Arctic ice could be gone in summer by mid-century. That alone wouldn’t raise sea levels, but bears watching because similar thaws in Antarctica could raise the oceans and flood low-lying areas. The recent dramatic melt "is a strong indication that there is an amplifying mechanism here," warned one scientist.